A vehicular portable device, which performs a remote control of a vehicular device, is known. The vehicular portable device remotely controls the vehicular device, such as locking or unlocking of a vehicle door by performing a short range wireless communication with a vehicular wireless device equipped to the vehicle.
A vehicular portable device, which is also capable of performing a near field communication (NFC) in addition to the short range wireless communication, is known. In Japan, the “short range wireless communication” also refers to the “near field communication” that is defined under ISO/IEC 18092. In the present disclosure, the “short range wireless communication” refers to a wireless communication having a communicable range longer than a communicable range of the “near field communication” defined under ISO/IEC 18092.
Among the short range wireless communication and the near field communication having different communicable ranges with one another, a mobile phone is known as one example of a communication device that is able to perform the near field communication. For example, in a mobile phone disclosed in patent literature 1, an antenna for radio-frequency identification (RFID) is adhered to an inner surface of a battery cover 8. The antenna for RFID corresponds to an NFC antenna.
In order to perform both the short range wireless communication and the near field communication, two antennas respectively corresponding to the short range wireless communication and the near field communication are necessary. However, a vehicular portable device has a compact size, and where to dispose the two antennas becomes a problem.
For example, in the above-described configuration, the two antennas for the two types of communications may be disposed on a substrate. However, on the substrate, a space for disposing the antennas is limited since various electronic components and a battery are disposed on the substrate. Further, patent literature 1 discloses that the antenna is adhered to the inner surface of the battery cover 8. With this configuration, a large size antenna can be provided to the vehicular portable device by adhering the antenna to the inner surface of the cover, compared with disposing the antenna on the substrate. However, the cover usually has a frame for assembling the cover with a case, and the battery cover 8 shown in patent literature 1 also has the frame. When adhering the antenna to the inner surface of the cover, the antenna is required to be adhered within the frame. Thus, only an antenna having a size smaller than an internal boundary of the frame can be adhered to the inner surface of the cover. Further, in the battery cover 8 disclosed in patent literature 1, multiple beams are formed on the inner surface of the battery cover 8 to secure a strength of the battery cover 8. Usually, various protrusions, such as beams are formed on the inner surface of the cover, not limited to patent literature 1. When adhering the antenna to the inner surface of the cover, a space to dispose the antenna is limited to an inside portion of the internal boundary of the frame of the cover, and the space is further limited by the multiple protrusions within the internal boundary of the frame of the cover. Thus, even though the antenna is adhered to the inner surface of the cover, a size of the antenna is required to be reduced caused by the above-described reasons.